This relates generally to storing information in memories and computers.
Conventionally, some memory types such as dual inline memory modules (DIMM) have no way to monitor the information being written into them. Thus, malicious code may be written into these memories, unknown to the internal memory controller.
Typically control over the types of data written is the responsibility of the host computer system that writes to the memory. But the host computer system generally implements writes through code driven by the operating system and applications thereon. These applications themselves may enable any check system to be overridden by malicious code.
As a result, memories generally have no protection against the storage of malicious code by the host computer system that may subsequently be used for various malicious activities.